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<H1 class="no-header">form_field_buffer 3x 2024-03-16 ncurses 6.5 Library calls</H1>
<PRE>
<STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>            Library calls           <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>form_field_buffer</STRONG> - field buffer control


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>

       <STRONG>int</STRONG> <STRONG>set_field_buffer(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>buf</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>value</EM><STRONG>);</STRONG>
       <STRONG>char</STRONG> <STRONG>*field_buffer(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>buffer</EM><STRONG>);</STRONG>

       <STRONG>int</STRONG> <STRONG>set_field_status(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>bool</STRONG> <EM>status</EM><STRONG>);</STRONG>
       <STRONG>bool</STRONG> <STRONG>field_status(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>);</STRONG>

       <STRONG>int</STRONG> <STRONG>set_max_field(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>max</EM><STRONG>);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
       The  function  <STRONG>set_field_buffer</STRONG>  sets  the numbered buffer of the given
       field to contain a given string:

          <STRONG>o</STRONG>   Buffer 0 is the displayed value of the field.

          <STRONG>o</STRONG>   Other numbered buffers may be allocated by applications  through
              the  <STRONG>nbuf</STRONG>  argument  of  (see  <STRONG><A HREF="form_field_new.3x.html">form_field_new(3x)</A></STRONG>)  but  are not
              manipulated by the forms library.

       The function <STRONG>field_buffer</STRONG> returns a pointer  to  the  contents  of  the
       given numbered buffer:

          <STRONG>o</STRONG>   The  buffer contents always have the same length, and are padded
              with trailing spaces as needed to  ensure  this  length  is  the
              same.

          <STRONG>o</STRONG>   The  buffer  may contain leading spaces, depending on how it was
              set.

          <STRONG>o</STRONG>   The buffer contents are set with <STRONG>set_field_buffer</STRONG>, or as a  side
              effect of any editing operations on the corresponding field.

          <STRONG>o</STRONG>   Editing  operations  are  based on the <EM>window</EM> which displays the
              field, rather than a <EM>string</EM>.  The window contains only printable
              characters,  and  is  filled  with  blanks.  If you want the raw
              data, you must write your own routine that copies the value  out
              of the buffer and removes the leading and trailing spaces.

          <STRONG>o</STRONG>   Because  editing  operations change the content of the buffer to
              correspond to the window, you should not rely on  using  buffers
              for long-term storage of form data.

       The function <STRONG>set_field_status</STRONG> sets the associated status flag of <EM>field</EM>;
       <STRONG>field_status</STRONG> gets the current value.  The  status  flag  is  set  to  a
       nonzero value whenever the field changes.

       The  function  <STRONG>set_max_field</STRONG> sets the maximum size for a dynamic field.
       An argument of 0 turns off any maximum size threshold for that field.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       The <STRONG>field_buffer</STRONG>  function  returns  NULL  on  error.   It  sets  <STRONG>errno</STRONG>
       according to their success:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_BAD_ARGUMENT</STRONG>
            Routine detected an incorrect or out-of-range argument.

       The <STRONG>field_status</STRONG> function returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.

       The remaining routines return one of the following:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_SYSTEM_ERROR</STRONG>
            System error occurred (see <STRONG>errno(3)</STRONG>).

       <STRONG>E_BAD_ARGUMENT</STRONG>
            Routine detected an incorrect or out-of-range argument.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       When  configured for wide characters, <STRONG>field_buffer</STRONG> returns a pointer to
       temporary  storage  (allocated  and  freed  by   the   library).    The
       application should not attempt to modify the data.  It will be freed on
       the next call to <STRONG>field_buffer</STRONG> to return the same buffer.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       These routines emulate the System  V  forms  library.   They  were  not
       supported on Version 7 or BSD versions.

       The   <STRONG>set_max_field</STRONG>   function   checks   for   an   <EM>ncurses</EM>  extension
       <STRONG>O_INPUT_FIELD</STRONG> which allows a dynamic field to shrink if the  new  limit
       is smaller than the current field size.


</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
       Raymond.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG> and related pages whose names  begin  "form_"  for  detailed
       descriptions of the entry points.



ncurses 6.5                       2024-03-16             <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>
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